Thyroid diagnostic modalities (fine needle aspiration and core needle biopsy) with histology correlation: a tertiary centre experience

Abstract

AimsTo determine the proportion of thyroid fine needle aspiration (FNA) and core needle biopsy (CNB) cases reported at a single institute into each UK Royal College of Pathologists (RCPath) Thy1-5 and local T category, respectively. Where subsequent histology was available, malignancy rates, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy were compared for both procedures.Methods1591 FNAs (2010–2018) and 514 CNBs (2013–2018) cases were identified, together with paired histology excision specimens.ResultsThe FNA samples were classified as: Thy1: 45.3%, Thy2/Thy2c: 22.1%, Thy3a/Thy3f: 28%, Thy4: 1.6% and Thy5: 3%; while the CNB were classified as: T1: 7.2%, T2: 22.4%, T3 59.3%, T4: 1% and T5: 10.1%. Comparison of FNA and CNB classified as Thy5/T5 showed a 100% risk of malignancy (ROM), sensitivity (98% vs 100%), specificity (14.1% vs 12.1%), PPV (29.4% vs 29.4%), NPV (94.9% vs 100%) and accuracy (36.5% vs 35.6%), respectively, for a diagnosis of malignancy. ROMs for other categories were: Thy1/T1 (9% vs 6.7%), Thy2/T2 (5.1% vs 0%), Thy3/T3 (17.5% vs 18.4%) and Thy4/T4 (73.3% vs 100%).ConclusionsThe proportion of cases in each RCPath Thy category has remained relatively stable during the 9-year study period, with the exception of the Thy3a category, which has increased over time. This finding is in line with other more recent reports in the literature and the proportion of T3 cases in the CNB group. The proportion of Thy2/Thy2c cases has also reduced over time, reflecting a local change in the triaging protocol for probable benign lesions. Both FNA and CNB showed comparable performance in our study.

2023 European Thyroid Association Clinical Practice Guidelines for thyroid nodule management

“…Core-needle biopsy (CNB), performed with a large bore spring-activated device, may provide a micro-histological sample from thyroid lesions. There are no clear advantages of using CNB, a more invasive and expensive procedure compared to FNA, based on cost and risk–benefit analysis ( 65 ).…”

Intraoperative Assessment of High-Risk Thyroid Nodules Based on Electrical Impedance Measurements: A Feasibility Study

“…In recent years, core needle biopsy (CNB) from thyroid nodules has been recommended for previous inconclusive FNAs [ 21 ]. Also, some researchers have confirmed that CNB could overcome the limitations of FNA in these lesions [ 10 , 13 , 22 , 23 ]. However, the role of CNB has not been well established for the assessment of thyroid nodules with suspicious US features [ 10 ].…”